1. Field of the Invention
The present invention relates to a card type electronic apparatus with multiple functions such as card-shaped electronic calculators, electronic memo pads, IC cards or the like.
2. Description of the Prior Art
As shown in FIG. 3, a conventional ordinary card type electronic apparatus such as an IC card or the like is provided with a magnetic stripe M, formed in the direction in which it is inserted into a device where it is to be installed, and external connection terminals T for the electric connection with the device. On the other hand, a multifunction card type electronic apparatus, which is provided with data input means that are operated by means of keys, display means that are operated by means of liquid crystals or the like and a power source for these means, is known, an example of which is shown in FIG. 4, wherein various electronic components 2 such as LSIs are mounted into a main circuit board 1, on one or both surfaces of which circuit patterns 3 are disposed. Bonded onto the top surface of the circuit board 1 is a surface protection panel 4 which is composed of an outer film 5 and an inner film 6. In the same way, bonded on the back surface of the circuit board 1 by means of a spacer member 13 is a back surface protection panel 7 which is composed of an outer film 8 and an inner film 9. Electronic components 2 are protected by these protection panels 4 and 7. A lead base 12 of the circuit board 1 on which external connection terminals 10, 11 are disposed is formed with a proper thickness in such a way that when the external connection terminals 10, 11 are mounted on the lead base 12, the top surface of each of the terminals 10, 11 become approximately flush with the top surface of the protection panel 4.
The reason why the lead base 12 of the circuit board 1 on which the external connection terminals 10, are disposed is made in a larger thickness than other portions of the circuit board 1 is that the position, shape and height of the external connection terminals 10, 11 are regulated by the International Standard Organization (ISO). Particularly the height is regulated so that the difference in height between the terminals and the outer film 5 is within .+-.0.1 mm. In a multifunction card type electronic apparatus, however, because the surface protection panel 4 composed of the outer film 5 and the inner film 6 exists on the surface of the circuit board 1 on which the external connection terminals 10, 11 are to be disposed, the requirement for the surface unevenness to be within .+-.0.1 mm can by no means be satisfied when the top surface of the circuit board 1 is made flat and external connection terminals 10, 11 are provided thereon. Such a circuit board 1 with locally different thicknesses leads to higher production cost because it requires additional processes including an etching process.